1 /* 2 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. 3 * All rights reserved. 4 * 5 * This source code is licensed under both the BSD-style license (found in the 6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 7 * in the COPYING file in the root directory of this source tree). 8 * You may select, at your option, one of the above-listed licenses. 9 */ 10 11 12 /* zstd_decompress_internal: 13 * objects and definitions shared within lib/decompress modules */ 14 15 #ifndef ZSTD_DECOMPRESS_INTERNAL_H 16 #define ZSTD_DECOMPRESS_INTERNAL_H 17 18 19 /*-******************************************************* 20 * Dependencies 21 *********************************************************/ 22 #include "mem.h" /* BYTE, U16, U32 */ 23 #include "zstd_internal.h" /* ZSTD_seqSymbol */ 24 25 26 27 /*-******************************************************* 28 * Constants 29 *********************************************************/ 30 static const U32 LL_base[MaxLL+1] = { 31 0, 1, 2, 3, 4, 5, 6, 7, 32 8, 9, 10, 11, 12, 13, 14, 15, 33 16, 18, 20, 22, 24, 28, 32, 40, 34 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 35 0x2000, 0x4000, 0x8000, 0x10000 }; 36 37 static const U32 OF_base[MaxOff+1] = { 38 0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D, 39 0xFD, 0x1FD, 0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD, 40 0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD, 41 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD }; 42 43 static const U32 OF_bits[MaxOff+1] = { 44 0, 1, 2, 3, 4, 5, 6, 7, 45 8, 9, 10, 11, 12, 13, 14, 15, 46 16, 17, 18, 19, 20, 21, 22, 23, 47 24, 25, 26, 27, 28, 29, 30, 31 }; 48 49 static const U32 ML_base[MaxML+1] = { 50 3, 4, 5, 6, 7, 8, 9, 10, 51 11, 12, 13, 14, 15, 16, 17, 18, 52 19, 20, 21, 22, 23, 24, 25, 26, 53 27, 28, 29, 30, 31, 32, 33, 34, 54 35, 37, 39, 41, 43, 47, 51, 59, 55 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803, 56 0x1003, 0x2003, 0x4003, 0x8003, 0x10003 }; 57 58 59 /*-******************************************************* 60 * Decompression types 61 *********************************************************/ 62 typedef struct { 63 U32 fastMode; 64 U32 tableLog; 65 } ZSTD_seqSymbol_header; 66 67 typedef struct { 68 U16 nextState; 69 BYTE nbAdditionalBits; 70 BYTE nbBits; 71 U32 baseValue; 72 } ZSTD_seqSymbol; 73 74 #define SEQSYMBOL_TABLE_SIZE(log) (1 + (1 << (log))) 75 76 typedef struct { 77 ZSTD_seqSymbol LLTable[SEQSYMBOL_TABLE_SIZE(LLFSELog)]; /* Note : Space reserved for FSE Tables */ 78 ZSTD_seqSymbol OFTable[SEQSYMBOL_TABLE_SIZE(OffFSELog)]; /* is also used as temporary workspace while building hufTable during DDict creation */ 79 ZSTD_seqSymbol MLTable[SEQSYMBOL_TABLE_SIZE(MLFSELog)]; /* and therefore must be at least HUF_DECOMPRESS_WORKSPACE_SIZE large */ 80 HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)]; /* can accommodate HUF_decompress4X */ 81 U32 rep[ZSTD_REP_NUM]; 82 } ZSTD_entropyDTables_t; 83 84 typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader, 85 ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock, 86 ZSTDds_decompressLastBlock, ZSTDds_checkChecksum, 87 ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage; 88 89 typedef enum { zdss_init=0, zdss_loadHeader, 90 zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage; 91 92 struct ZSTD_DCtx_s 93 { 94 const ZSTD_seqSymbol* LLTptr; 95 const ZSTD_seqSymbol* MLTptr; 96 const ZSTD_seqSymbol* OFTptr; 97 const HUF_DTable* HUFptr; 98 ZSTD_entropyDTables_t entropy; 99 U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32]; /* space needed when building huffman tables */ 100 const void* previousDstEnd; /* detect continuity */ 101 const void* prefixStart; /* start of current segment */ 102 const void* virtualStart; /* virtual start of previous segment if it was just before current one */ 103 const void* dictEnd; /* end of previous segment */ 104 size_t expected; 105 ZSTD_frameHeader fParams; 106 U64 decodedSize; 107 blockType_e bType; /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */ 108 ZSTD_dStage stage; 109 U32 litEntropy; 110 U32 fseEntropy; 111 XXH64_state_t xxhState; 112 size_t headerSize; 113 ZSTD_format_e format; 114 const BYTE* litPtr; 115 ZSTD_customMem customMem; 116 size_t litSize; 117 size_t rleSize; 118 size_t staticSize; 119 int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */ 120 121 /* dictionary */ 122 ZSTD_DDict* ddictLocal; 123 const ZSTD_DDict* ddict; /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */ 124 U32 dictID; 125 int ddictIsCold; /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */ 126 127 /* streaming */ 128 ZSTD_dStreamStage streamStage; 129 char* inBuff; 130 size_t inBuffSize; 131 size_t inPos; 132 size_t maxWindowSize; 133 char* outBuff; 134 size_t outBuffSize; 135 size_t outStart; 136 size_t outEnd; 137 size_t lhSize; 138 void* legacyContext; 139 U32 previousLegacyVersion; 140 U32 legacyVersion; 141 U32 hostageByte; 142 int noForwardProgress; 143 144 /* workspace */ 145 BYTE litBuffer[ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH]; 146 BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX]; 147 }; /* typedef'd to ZSTD_DCtx within "zstd.h" */ 148 149 150 /*-******************************************************* 151 * Shared internal functions 152 *********************************************************/ 153 154 /*! ZSTD_loadDEntropy() : 155 * dict : must point at beginning of a valid zstd dictionary. 156 * @return : size of entropy tables read */ 157 size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy, 158 const void* const dict, size_t const dictSize); 159 160 /*! ZSTD_checkContinuity() : 161 * check if next `dst` follows previous position, where decompression ended. 162 * If yes, do nothing (continue on current segment). 163 * If not, classify previous segment as "external dictionary", and start a new segment. 164 * This function cannot fail. */ 165 void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst); 166 167 168 #endif /* ZSTD_DECOMPRESS_INTERNAL_H */ 169